Experimental Particle Physics Research Group

PhD projects

Funded PhD studentships

We are currently accepting applications for STFC and University funded studentships in our group for a September 2023 start. Interviews for shortlisted candidates are expected to be held in February and March initially and will continue until the positions are filled. Please apply using the online application form.

Some examples of current projects available:

BSM Physics with the Top Quark – ATLAS Experiment

Lacking clear signals of physics Beyond the Standard Model (BSM) at the Large Hadron Collider, it is imperative to investigate whether small physics contributions from new phenomena may affect either rare or kinematically difficult Standard Model processes. Focusing mainly on the associated production of top and bottom quarks with vector bosons or missing transverse momentum from the production of invisible dark matter particles, the candidate will develop a strategy to use search techniques together with inclusive and differential cross section measurements sensitive to different BSM processes, also using the framework of Standard Model Effective Field Theories. Given the current limits, advanced analysis techniques, possibly involving the use of machine learning techniques, will have to be explored. The ATLAS-Sussex group has a remarkable track record in investigating new physics connected with third generation quarks, in particular in the area of supersymmetry and dark matter production. The group has also had significant contributions in measurements of ttZ, ttW, ttH production mainly in multilepton final states. Profiting from this expertise, the candidate will be ideally positioned to make large impact in this sector, also through close contact with CERN-based experts.

SNO+ Reactor Antineutrino Oscillations

Applications are invited from talented and creative students for a PhD place in Experimental Particle Physics, to join the Sussex group working on the SNO+ experiment under the supervision of Dr Lisa Falk. SNO+ offers a rich programme of neutrino physics, which includes neutrinoless double beta decay, antineutrinos from reactors and geothermal activity, solar neutrinos and a supernova watch. It is located at SNOLAB, 2 km underground in the Creighton mine in Canada. The experiment recently completed the filling of liquid scintillator. Data-taking, which commenced in 2017, will continue as we prepare for the introduction of the double beta decay isotope. The successful candidate is expected to work on the analysis of antineutrinos from nearby nuclear reactors, focusing on an oscillation measurement that will help resolve the current 2 sigma difference between the solar and reactor neutrino results from previous experiments. The student will also spend some fraction of their time developing software for the calibration of the experiment and for data quality assurance, as well as participating in SNO+ experimental operations. The project is likely to involve spending an extended period of time at SNOLAB. (Supervisor: Dr. Lisa Falk)

Investigating the nature of reality by measuring the properties top quarks and Higgs bosons with ATLAS

Probing the Higgs boson, the most recently discovered fundamental particle, and one unlike anything else in the SM, is a critical priority in the search for new physics at the LHC. The Higgs boson is responsible for giving fundamental particles their mass and has the strongest interaction with the largest mass particles. The top quark is the heaviest fundamental particle in the SM and therefore has the strongest coupling to the Higgs. This makes LHC collisions where a Higgs is produced with a top-quark pair (ttH) one of the most exciting places to look for signs of new physics. The interaction of top quarks and leptons (ttll) as well as being an important background to ttH measurements is also of extremely high priority in its own right as it gives a window into one of the strongest hints of new physics to come out of the LHC, the flavour anomalies. The candidate will play a leading role in new differential measurements of ttH in the H->leptons decay mode. This will provide fresh sensitivity to the top quark-Higgs interaction and the Higgs boson’s interaction with itself that will lead to world-leading sensitivity to new physics. The importance of this work goes beyond understanding the Higgs boson. The interplay between the strength of the top-Higgs interaction and the Higgs self-interaction is directly related to the stability of the Universe at a quantum level and the exact (CP) nature of the top-Higgs interaction could hold the answer to why we exist at all - why the Universe is matter-dominated. The candidate will also investigate in detail the main backgrounds to this analysis, including a measurement of ttll (where l=e,mu,tau) to test the universality of lepton couplings in the top sector. This measurement will add a vital additional piece of information in our attempts to understand the flavour anomalies seen in the B-sector. (Supervisor: Dr Josh McFayden)

SBND Neutrino Detector Commissioning and Search for Dark Neutrinos

A studentship is available to work on the SBND experiment under the supervision of Dr Clark Griffith. A number of experiments have shown anomalies in neutrino oscillation results, hinting at a possible additional neutrino state beyond the three present in the Standard Model. The Short Baseline Neutrino (SBN) programme at Fermilab aims to settle the question of whether or not the anomalies are real or not, with a set of three large liquid argon TPC neutrino detectors: ICARUS, MicroBooNE, and the Short Baseline Near Detector (SBND). SBND will begin commissioning in 2023, and this project will initially focus on tuning and optimisation of the detector with commissioning data, with the opportunity to spend a significant amount of time located at Fermilab during this crucial and exciting stage of the SBN programme. The project will also involve an analysis searching for evidence of dark neutrino signals in SBND data, a possible Beyond the Standard Model (BSM) explanation for short baseline anomalies seen in the MiniBooNE experiment. (Supervisor: Dr W Clark Griffith)

Opaque Scintillator Detector R&D and NOvA Neutrino Oscillation Analysis

A studentship is available involving working on the NOvA neutrino experiment and doing detector R&D under the supervision of Prof Jeff Hartnell. On NOvA you will have the opportunity to work towards answering the question of the neutrino mass hierarchy and to develop the search for leptonic CP violation. The group plays leading roles in both the 3-flavour neutrino oscillation analysis and the joint analysis with T2K. Across NOvA, reconstruction, machine learning and calibration are areas of expertise. The Sussex group has a long history of neutrino research and a number of senior leadership roles internationally, including overall physics analysis coordination for NOvA. For the detector R&D part you will have the opportunity to work on the exciting new idea of using opaque scintillators. Instead of relying on light travelling to the outside of a transparent scintillator, a lattice of fibre optic cables is embedded in an opaque scintillator that allows light to be collected near its point of origin. This concept is expected to have many applications since it combines high resolution and fast imaging of particle interactions with what is expected to be relatively straightforward, lower-cost manufacture. This project also includes the opportunity to spend an extended period of time at Fermilab in the USA or at a lab in Europe. (Supervisor: Prof Jeff Hartnell)


PhD projects available for self-funded students

These projects are available for students that are able to self-fund their PhD studies, or have an externally funded scholarship. Applications for these studentships are welcome at any time of year. Any of the funded projects listed in the previous section are also in principle available to self funded applicants. Please contact the listed supervisor if interested.

FASER(2): Looking forward to new physics

FASER stands for “ForwArd Search ExpeRiment” and is one the newest experiments based at the Large Hadron Collider (LHC) at CERN. It is a novel experiment searching for exotic long-lived and weakly-interacting new particles. Such particles are excellent candidates to explain the existence of Dark Matter. If they exist, these exotic particles would be produced in collisions inside the ATLAS detector and detected nearly 500m away in FASER. The Sussex EPP group has had involvement in the construction and commissioning of the FASER detector that is now installed underground at CERN. FASER is currently taking data during LHC Run 3 and the candidate will make major contributions to the analysis of this data with a view to probing brand new areas of phase-space that have until now been experimentally out of reach. The analysis of the data will involve understanding the performance of the detector and backgrounds to be then be able to search for possible signs of new particles. In addition, R&D studies are underway for a significantly upgraded detector to FASER, known as FASER2. This detector would be housed in the Forward Physics Facility and would be installed in next, high-luminosity (HL), phase of running for the LHC (Run 4) and would take data until the end of HL-LHC. The candidate will investigate different designs of FASER2 to determine what layouts and detector technologies will be required to get the best sensitivity to new particles. They would in particular be expected to focus on the design and prototyping of the calorimeter which is currently foreseen to make use of a novel dual-readout technology which would also relevant for future colliders after the LHC. The Sussex Collider physics group has made significant contributions to the construction, commissioning and operation of FASER and is leading R&D efforts on FASER2: profiting from this experience in the group, the candidate will be ideally positioned to make large impact in this sector, also through close contact with CERN-based experts. (Supervisor: Dr Josh McFayden)

R&D for Future Colliders

The worldwide particle physics (HEP) community is gearing up for the construction of a new electron-positron collider. This machine will give unprecedented precision for the measurement of crucial Standard Model parameters, particularly the Higgs boson, and have interesting prospects for the discovery of new physics phenomena. The challenges presented to the HEP community in relation to this new project come from having to design new ‘frontier’ detectors for a completely new e+ e- collider. The Sussex Collider group is part of a 4-year international EU network (AIDAInnova) and is leading the UK effort in two crucial areas of the R&D for future colliders: the development of a novel concept of calorimeter, which will allow measuring hadronic signals with high resolution; and the development of Trigger and Data Acquisition platforms for the R&D of novel detectors, including the monitoring of signals from different detector prototypes at test beams. 

The following projects on R&D for future colliders are available for self-funded students under the supervision of Prof Fabrizio Salvatore and Prof Iacopo Vivarelli:

  • The development and test of the optical readout of a novel dual-readout calorimeter prototype, which will be extensively tested at beam tests at CERN (Geneva, Switzerland) and DESY (Hamburg, Germany) for the duration of the project;
  • The development of generic data acquisition software tools to be deployed on the calorimeter and generalised to other detectors tested on the beam lines during the R&D of detector prototypes;
  • The development and application of particle flow techniques to simulated calorimeter data for the determination of calorimeter resolutions and general physics studies for future collider experiments.

The ideal candidate would have some experience in C++ and python programming, and knowledge of particle interaction with matter. The candidate will be ideally positioned to make a large impact in this sector, also through close contact with the other nodes of the network and with CERN- and DESY-based experts.

Tackling Traditional and AI Computing Challenges with FPGA Accelerators

As particle detectors evolve in response to more demanding conditions and stringent requirements, and in parallel to the dataset size, the complexity of events processing is increasing. The computing requirements of the highest priority projects within the UK HEP programme are posing significant challenges which must be addressed head-on. The four LHC experiments (ATLAS, CMS, LHCb and ALICE) recorded almost 1 exabyte of data to make groundbreaking discoveries, from the Higgs Boson to pentaquarks. Major upgrades of the LHC experiments are due to take place in the 2020s which will greatly augment their datasets, while in parallel we will see the build-up to operation of the next generation of neutrino experiments (DUNE and Hyper-Kamiokande) with LHC-scale volumes of highly granular data. To exploit the full physics potential offered by the large data sets collected by the next-generation experiments, new hardware, software and algorithmic techniques are required to handle their production rate, volume, and complexity. The existing solutions, e.g. in the reconstruction of detector data, have largely evolved from an era of entirely different hardware and software technologies, and are completely inadequate for the task. Scientific computing is moving towards the use of accelerator hardware, such as GPUs and FPGAs, where thousands of threads operate simultaneously to perform fast scientific computations. This is an opportunity, as real-time applications such as low latency triggers can be developed using commodity hardware and software tools. 

FPGA accelerators offer a paradigm shift in computing acceleration, especially with the advent of “High Level Synthesis” (HLS) tools: they offer an algorithmic speed and efficiency akin to that of a dedicated circuit-level implementation together with the programmability of a regular processor. This is often coupled – in commercial solutions – to I/O capabilities unprecedented in the realm of computing accelerators.

Prof. Alessandro Cerri is establishing at Sussex an FPGA accelerator R&D facility, which offers a quite unique set of resources in the UK for this kind of research technology. 

This research project aims at the use of High Level Synthesis implementations of pattern recognition and other critical algorithms for online and offline data selection, analysis, and reconstruction. The project will focus on the implementation of such solutions in future collider environments (e.g. in the challenging background conditions foreseen at muon collider experiments), and the documentation of guidelines and practices to the benefit of the community.

The project could potentially also involve a fraction of the time devoted to the investigation of applications beyond particle physics, including:

  • The interface capability of these accelerators opens up the possibility of commercial solutions to the problem of data acquisition and processing in small experimental set-ups.
  • The same algorithmic strategies have a wide range of potential inter-disciplinary applications: from genetic sequencing to medical imaging to financial market real-time predictions and decisions.